opencv: GST_EXPORT -> GST_OPENCV_API

We need different export decorators for the different libs.
For now no actual change though, just rename before the release,
and add prelude headers to define the new decorator to GST_EXPORT.

gst-libs/gst/opencv/Makefile.am

diff --git a/gst-libs/gst/opencv/Makefile.am b/gst-libs/gst/opencv/Makefile.am
index 9d18a5f..cc0d67f 100644
--- a/gst-libs/gst/opencv/Makefile.am
+++ b/gst-libs/gst/opencv/Makefile.am
@@ -5,6 +5,7 @@
 	gstopencvvideofilter.cpp
 
 libgstopencv_@GST_API_VERSION@_la_CXXFLAGS = \
+	$(GST_PLUGINS_BAD_CFLAGS) \
 	$(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CXXFLAGS) \
 	$(OPENCV_CFLAGS)
 
@@ -17,5 +18,6 @@
 libgstopencv_@GST_API_VERSION@includedir = \
 	$(includedir)/gstreamer-@GST_API_VERSION@/gst/opencv
 libgstopencv_@GST_API_VERSION@include_HEADERS = \
+	opencv-prelude.h \
 	gstopencvutils.h \
 	gstopencvvideofilter.h

gst-libs/gst/opencv/gstopencvutils.h

diff --git a/gst-libs/gst/opencv/gstopencvutils.h b/gst-libs/gst/opencv/gstopencvutils.h
index d6aa6ca..3b74cc9 100644
--- a/gst-libs/gst/opencv/gstopencvutils.h
+++ b/gst-libs/gst/opencv/gstopencvutils.h
@@ -28,24 +28,25 @@
 
 #include <gst/gst.h>
 #include <gst/video/video.h>
+#include <gst/opencv/opencv-prelude.h>
 
 G_BEGIN_DECLS
 
-GST_EXPORT
+GST_OPENCV_API
 gboolean gst_opencv_parse_iplimage_params_from_caps
     (GstCaps * caps, gint * width, gint * height, gint * depth,
     gint * channels, GError ** err);
 
-GST_EXPORT
+GST_OPENCV_API
 gboolean gst_opencv_iplimage_params_from_video_info
     (GstVideoInfo * info, gint * width, gint * height, gint * depth,
     gint * channels, GError ** err);
 
-GST_EXPORT
+GST_OPENCV_API
 gboolean gst_opencv_cv_image_type_from_video_format (GstVideoFormat format,
     int * cv_type, GError ** err);
 
-GST_EXPORT
+GST_OPENCV_API
 GstCaps * gst_opencv_caps_from_cv_image_type (int cv_type);
 
 G_END_DECLS

gst-libs/gst/opencv/gstopencvvideofilter.h

diff --git a/gst-libs/gst/opencv/gstopencvvideofilter.h b/gst-libs/gst/opencv/gstopencvvideofilter.h
index 2aa43e9..58f1bda 100644
--- a/gst-libs/gst/opencv/gstopencvvideofilter.h
+++ b/gst-libs/gst/opencv/gstopencvvideofilter.h
@@ -46,6 +46,7 @@
 
 #include <gst/gst.h>
 #include <gst/video/gstvideofilter.h>
+#include <gst/opencv/opencv-prelude.h>
 
 G_BEGIN_DECLS
 
@@ -101,10 +102,10 @@
   GstOpencvVideoFilterSetCaps cv_set_caps;
 };
 
-GST_EXPORT
+GST_OPENCV_API
 GType gst_opencv_video_filter_get_type (void);
 
-GST_EXPORT
+GST_OPENCV_API
 void gst_opencv_video_filter_set_in_place (GstOpencvVideoFilter * transform,
                                            gboolean ip);
 

gst-libs/gst/opencv/meson.build

diff --git a/gst-libs/gst/opencv/meson.build b/gst-libs/gst/opencv/meson.build
index 80639d3..ba132aa 100644
--- a/gst-libs/gst/opencv/meson.build
+++ b/gst-libs/gst/opencv/meson.build
@@ -4,6 +4,7 @@
 ]
 
 opencv_headers = [
+  'opencv-prelude.h',
   'gstopencvutils.h',
   'gstopencvvideofilter.h',
 ]

gst-libs/gst/opencv/opencv-prelude.h

diff --git a/gst-libs/gst/opencv/opencv-prelude.h b/gst-libs/gst/opencv/opencv-prelude.h
new file mode 100644
index 0000000..2cbea56
--- /dev/null
+++ b/gst-libs/gst/opencv/opencv-prelude.h
@@ -0,0 +1,31 @@
+/* GStreamer OpenCV Library
+ * Copyright (C) 2018 GStreamer developers
+ *
+ * opencv-prelude.h: prelude include header for gst-opencv library
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __GST_OPENCV_PRELUDE_H__
+#define __GST_OPENCV_PRELUDE_H__
+
+#include <gst/gst.h>
+
+#ifndef GST_OPENCV_API
+#define GST_OPENCV_API GST_EXPORT
+#endif
+
+#endif /* __GST_OPENCV_PRELUDE_H__ */